Interaural time differences (ITDs) are a dominant cue for the perception for auditory space. New hypotheses concerning the mechanism of ITD sensitivity and its representations have been developed based on recordings from each level of the auditory system in an unanesthetized preparation. For this study, I intend to test this hypotheses through recordings and connectional studies in the auditory cortex. The specific aims are to: 1) identify the topography of ITD representation in the primary auditory cortex in relation to parameters that determine ITD tuning in individual neurons, 2) determine the distribution of response properties in different cortical layers, and 3) study the flow of ITD information from primary cortex to other areas. My long-term goal is to understand the performance of this major sensory system in terms of the physiological responses of single neurons and neural populations, and test this understanding against behavior. The expected health benefits include the development of devices, software, or prostheses that use the principles discovered to assist hearing-impaired individuals.